<!DOCTYPE html>
<html lang="en">
  <head>
    <meta charset="UTF-8" />
    <meta name="viewport" content="width=device-width, initial-scale=1.0" />
    <title>Document</title>
  </head>
  <body>
    <script>
      "use strict";
      const Fn = function () {
        // let this = {}
        this.name = "jack";
        // return this; // this
        // return 100; // this
        return { age: 20 };
      };
      const fn = new Fn();
      console.log(fn.age);
      console.log(new Fn().age);
      console.log(
        new (function () {
          // let this = {}
          this.name = "jack";
          // return this; // this
          // return 100; // this
          return { age: 20 };
        })().age
      );
    </script>
  </body>
</html>
